Age, nutrition and genetics. If the deer is not 3.5 - 4.5 yrs old is has not started to mature. If the deer does not have the genetics it cannot possibly produce. If the deer has the genetics and is allowed to age but does not have the proper nutrition the equation is imbalanced and genetic potential will not be reached. High protein during the antler/lactation period are a good start. Other things such foods high in carbs during the Sept. - March period are another. Good vitamin/mineral content in the soil is a must or supplements must be put out. A forage crop with some supplements during the green up period is a good start. Some high carb annuals for after is next. Each management area has it' s own unique needs.